Is it sufficient to stretch my legs, back, and arms? How do you stretch your neck, for instance? Any recommended stretches, especially for posture?

Morning fellow fabulous user. For your posture, start with balancing a book on your head, then take a few steps also. That is the best way i know to straighten your posture. Stretching your neck,do side turns, chin to shoulder; left,right back & fourth. Also touch chin to chest; start with about 5-10 reps to start.
I hope this helps you, & happy stretching..🌷☺

Legs, back and arms are always great to stretch and the neck is just as important. It helps with your shoulder muscles too. One if the best neck stretches I do is: stand with your feet shoulder width apart and toes facing forward. Knees relaxed , tailbone down to floor not arched lower back. Shoulders and arms relaxed and at the sides. Looking straight ahead drop your chin down to your chest and relax. Hold for 5 counts and then slowly bring it back up. Repeat 3 times. Next drop your ear to your shoulder and hold for 5 counts and slowly come back to the centre and then repeat to the other side. Do this 3 times on each side. It helps to stretch both sides of the neck and shoulder. Oh and don't forget to breathe 😀

There is a free app in the Play Store from Leap Fitness Group called stretching exercises. It's literally dedicated to only stretching. I love the night and morning routines. They are easy to do and follow and always leave me feeling calm and either ready for bed or to start my day. You can even make your own routine(on the app) based off of the poses that they have then save it to use whenever you don't want to use one of theirs. I hope it helps you as well. ✨